The intestinal microbiome plays an important role in the metabolism of chemical compounds found within food. Bacterial metabolites are different from those that can be generated by human enzymes because bacterial processes occur under anaerobic conditions and are based mainly on reactions of reduction and/or hydrolysis. In most cases, bacterial metabolism reduces the activity of dietary compounds; however, sometimes a specific product of bacterial transformation exhibits enhanced properties. Studies on the metabolism of polyphenols by the intestinal microbiota are crucial for understanding the role of these compounds and their impact on our health. This review article presents possible pathways of polyphenol metabolism by intestinal bacteria and describes the diet-derived bioactive metabolites produced by gut microbiota, with a particular emphasis on polyphenols and their potential impact on human health. Because the etiology of many diseases is largely correlated with the intestinal microbiome, a balance between the host immune system and the commensal gut microbiota is crucial for maintaining health. Diet-related and age-related changes in the human intestinal microbiome and their consequences are summarized in the paper.

Acrylamide (AA) and its metabolites have been recognized as potential carcinogens, but also they can cause other negative symptoms in human or animal organisms and therefore this class of chemical compounds has attracted a lot of attention. These substances are usually formed when heating asparagine in the presence of compounds that have α-hydroxycarbonyl groups, α,β,γ,δ-diunsaturated carbonyl groups or α-dicarbonyl groups. The acrolein pathway and enzymatic decarboxylation of asparagine, as well as endogenic processes, are other alternative routes to AA formation. It has been demonstrated that the animal model used for examining AA toxicity may not be sufficient to investigate these changes in humans, therefore it is necessary to design an in vitro model, which could provide more accurate insights into the direction of these processes in human organisms. Acrylamide can be metabolized through both oxidative and reductive pathways; moreover, there is also a chance that some representatives of intestinal microbiota are able to transform acrylamide. It was shown that there are various microorganisms, mostly bacteria, that produce amidases, i.e. enzymes decomposing AA. Lactic acid bacteria also appear to demonstrate the ability to use acrylamide as a carbon source, but this still requires further investigation. Another way to prevent AA toxicity is related to the presence of some food compounds, such as certain proteins or polyphenols. There are still lot of gaps in the current knowledge related to AA toxicity, so future potential research directions are presented in this review as well.

Growing consumer interest in new beer flavors is contributing to the application of innovative materials and non-Saccharomyces yeast in brewing. The goal of this study was to test the impact of the low lactic acid-producing Lachancea thermotolerans MN477031 strain on the process of fermenting beer wort, with two different concentrations of bitter compounds, and on the quality of the beer produced. Qualify factors were broadly analyzed, including ethanol content, apparent degree of fermentation, sugars, organic acids, free amino nitrogen, glycerol, volatile compounds, ions and so on. It was proven that the L. thermotolerans MN477031 strain demonstrated a high capacity for rapid initiation of wort fermentation, and a tolerance to hop-derived compounds. As a result, the alcohol content in beer from this method of production was approximately 20% lower, while the content of the real extract was significantly higher in comparison to commercial Safbrew T-58. This strain stands out from many strains of L. thermotolerans due to the low lactic acid production and only marginal influence on pH decrease compared to Saccharomyces cerevisiae. Therefore, the potential of MN477031 in the production of different types of beer (not only sour) is very high. The composition of volatile compounds in L. thermotolerans beer differs—not only in terms of the use of the strain, but also in hop variety.